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The complex structure of Timeless_PAB and PARP-1_catalytic domain
Structural highlights
FunctionTIM_HUMAN Plays an important role in the control of DNA replication, maintenance of replication fork stability, maintenance of genome stability throughout normal DNA replication and in the regulation of the circadian clock. Involved in the determination of period length and in the DNA damage-dependent phase advancing of the circadian clock. Negatively regulates CLOCK|NPAS2-ARTNL/BMAL1|ARTNL2/BMAL2-induced transactivation of PER1 possibly via translocation of PER1 into the nucleus. Forms a complex with TIPIN and this complex regulates DNA replication processes under both normal and stress conditions, stabilizes replication forks and influences both CHEK1 phosphorylation and the intra-S phase checkpoint in response to genotoxic stress. Timeless promotes TIPIN nuclear localization. Involved in cell survival after DNA damage or replication stress. May be specifically required for the ATR-CHEK1 pathway in the replication checkpoint induced by hydroxyurea or ultraviolet light. May also play an important role in epithelial cell morphogenesis and formation of branching tubules.[1] [2] [3] [4] Publication Abstract from PubMedHuman Timeless helps stabilize replication forks during normal DNA replication and plays a critical role in activation of the S phase checkpoint and proper establishment of sister chromatid cohesion. However, it remains elusive whether Timeless is involved in the repair of damaged DNA. Here, we identify that Timeless physically interacts with PARP-1 independent of poly(ADP-ribosyl)ation. We present high-resolution crystal structures of Timeless PAB (PARP-1-binding domain) in free form and in complex with PARP-1 catalytic domain. Interestingly, Timeless PAB domain specifically recognizes PARP-1, but not PARP-2 or PARP-3. Timeless-PARP-1 interaction does not interfere with PARP-1 enzymatic activity. We demonstrate that rapid and transient accumulation of Timeless at laser-induced DNA damage sites requires PARP-1, but not poly(ADP-ribosyl)ation and that Timeless is co-trapped with PARP-1 at DNA lesions upon PARP inhibition. Furthermore, we show that Timeless and PARP-1 interaction is required for efficient homologous recombination repair. Timeless Interacts with PARP-1 to Promote Homologous Recombination Repair.,Xie S, Mortusewicz O, Ma HT, Herr P, Poon RR, Helleday T, Qian C Mol Cell. 2015 Sep 2. pii: S1097-2765(15)00589-4. doi:, 10.1016/j.molcel.2015.07.031. PMID:26344098[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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